Abstract New neutrino–nucleus interaction cross-section measurements are required to improve nuclear models sufficiently for future long baseline neutrino experiments to meet their sensitivity goals. ...A time projection chamber (TPC) filled with a high-pressure gas is a promising detector to characterise the neutrino sources used for such experiments. A gas-filled TPC is ideal for measuring low-energy particles, which travel further in gas than in solid or liquid detectors and using high-pressure increases the target density, resulting in more neutrino interactions. We examine the suitability of multiwire proportional chambers (MWPCs) from the ALICE TPC for use as the readout chambers of a high-pressure gas TPC. These chambers were previously operated at atmospheric pressure. We report the successful operation of an ALICE TPC outer readout chamber (OROC) at pressures up to 4.2 bar absolute (barA) with $$\text {Ar-CH}_4$$ Ar-CH 4 mixtures with a $$\text {CH}_{4}$$ CH 4 content between 2.8 and 5.0%, and so far up to 4 bar absolute with $${\text {Ar-CO}}_2$$ Ar-CO 2 (90-10). The charge gain of the OROC was measured with signals induced by an $$^{55}\text {Fe}$$ 55 Fe source. The largest gain achieved at 4.2 bar was $$(29\pm 1)\cdot 10^{3}$$ ( 29 ± 1 ) · 10 3 in $$\text {Ar-CH}_4$$ Ar-CH 4 with 4.0% $$\text {CH}_{4}$$ CH 4 with an anode voltage of $${2975}\,\hbox {V}$$ 2975 V . In $${\text {Ar-CO}}_2$$ Ar-CO 2 with 10% $$\text {CO}_{2}$$ CO 2 at 4 barA, a gain of $$(4.2\pm 0.1)\cdot 10^{3}$$ ( 4.2 ± 0.1 ) · 10 3 was observed with anode voltage $${2975}\,\hbox {V}$$ 2975 V . We extrapolate that at 10 barA, an interesting pressure for future neutrino experiments, a gain of 5000 in $${\text {Ar-CO}}_2$$ Ar-CO 2 with 10% $$\text {CO}_{2}$$ CO 2 (10,000 in $$\text {Ar-CH}_4$$ Ar-CH 4 with $$\sim \!{4}{\%}$$ ∼ 4 % $$\text {CH}_{4}$$ CH 4 ) may be achieved with anode voltage of $${4.6}\,\hbox {kV}$$ 4.6 kV ( $$\sim \!{3.6}\,\hbox {kV}$$ ∼ 3.6 kV ).
A High Pressure TPC with Optical Readout Waldron, A. V.; Deisting, A.
2019 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC),
2019-Oct.
Conference Proceeding
A High Pressure Time Projection Chamber (HPTPC) with hybrid optical and charge readout has been developed and tested for use in future neutrino oscillation experiments. In this talk we present ...preliminary results demonstrating the optical and charge readout.
New neutrino-nucleus interaction cross-section measurements are required to improve nuclear models sufficiently for future long-baseline neutrino experiments to meet their sensitivity goals. A time ...projection chamber (TPC) filled with a high-pressure gas is a promising detector to characterise the neutrino sources planned for such experiments. A gas-filled TPC is ideal for measuring low-energy particles as they travel much further in gas than solid or liquid neutrino detectors. Using a high-pressure gas increases the target density, resulting in more neutrino interactions. This paper will examine the suitability of multiwire proportional chambers (MWPCs) taken from the ALICE TPC to be used as the readout chambers of a high-pressure gas TPC. These chambers were previously operated at atmospheric pressure. We tested one such MWPC at up to almost 5 bar absolute (barA) with the UK high-pressure test stand at Royal Holloway, University of London. This paper reports the successful operation of an ALICE TPC outer readout chamber (OROC) at pressures up to 4.8 bar absolute with Ar-CH\(_{4}\) mixtures with a CH\(_{4}\) content between 2.8% and 5.0%, and so far up to 4 bar absolute with Ar-CO\(_{2}\) (90-10). We measured the charge gain of this OROC using signals induced by an \(^{55}\)Fe source. The largest gain achieved at 4.8 bar was \(64\pm2)\cdot10^{3}\) at stable conditions with an anode wire voltage of 2990 V in Ar-CH\(_{4}\) (95.9-4.1). In Ar-CO\(_{2}\) a gain of \((4.2\pm0.1)\cdot10^{3}\) was observed at an anode voltage of 2975 V at 4 barA gas pressure. Based on all our gain measurements, we extrapolate that, at the 10 barA pressure necessary to fit 1 tonne of gas into the ALICE TPC volume, a gain of 5000 in Ar-CO\(_{2}\) (90-10) (10000 in Ar-CH\(_{4}\) with \(\sim\!\) 4% CH\(_{4}\) content) may be achieved with an OROC anode voltage of 4.2 V (\(\sim\!\) 3.1 kV).
Xenon dual-phase time projections chambers (TPCs) have proven to be a successful technology in studying physical phenomena that require low-background conditions. With 40t of liquid xenon (LXe) in ...the TPC baseline design, DARWIN will have a high sensitivity for the detection of particle dark matter, neutrinoless double beta decay (\(0\nu\beta\beta\)), and axion-like particles (ALPs). Although cosmic muons are a source of background that cannot be entirely eliminated, they may be greatly diminished by placing the detector deep underground. In this study, we used Monte Carlo simulations to model the cosmogenic background expected for the DARWIN observatory at four underground laboratories: Laboratori Nazionali del Gran Sasso (LNGS), Sanford Underground Research Facility (SURF), Laboratoire Souterrain de Modane (LSM) and SNOLAB. We determine the production rates of unstable xenon isotopes and tritium due to muon-included neutron fluxes and muon-induced spallation. These are expected to represent the dominant contributions to cosmogenic backgrounds and thus the most relevant for site selection.
The World Health Organisation (WHO) presents an upper limit for lead in drinking water of 10 parts per billion ppb. Typically, to reach this level of sensitivity, expensive metrology is required. To ...increase the sensitivity of low cost devices, this paper explores the prospects of using a volume reduction technique of a boiled water sample doped with Lead-210 (\(^{210}Pb\)), as a means to increase the solute's concentration. \(^{210}\)Pb is a radioactive lead isotope and its concentration in a water sample can be measured with e.g. High Purity Germanium (HPGe) detectors at the Boulby Underground Germanium Suite. Concentrations close to the WHO limit have not been examined. This paper presents a measurement of the volume reduction technique retaining \(99\pm(9)\%\) of \(^{210}\)Pb starting from a concentration of \(1.9\times10^{-6}\) ppb before reduction and resulting in \(2.63\times10^{-4}\) ppb after reduction. This work also applies the volume reduction technique to London tap water and reports the radioassay results from gamma counting in HPGe detectors. Among other radio-isotopes, \(^{40}\)K, \(^{210}\)Pb, \(^{131}\)I and \(^{177}\)Lu were identified at measured concentrations of \(2.83\times10^{3}\) ppb, \(2.55\times10^{-7}\) ppb, \(5.06\times10^{-10}\) ppb and \(5.84\times10^{-10}\) ppb in the London tap water sample. This technique retained \(90\pm50\%\) of \(^{40}\)K. Stable lead was inferred from the same water sample at a measured concentration of 0.012 ppb, prior to reduction.
This paper reports on the development of a novel CMOS device employing lead-sensing bacteria to assay lead in drinking water. The objective of the PlomBOX project is to develop a low-cost sensor ...({\pounds}10) which can expedite access to on-demand assay methods and thus help mitigate lead intake through contaminated drinking water. The project follows three development paths: a) Certain bacteria can fluoresce or change colour when in the presence of lead. A genetically modified strain of Escherichia coli sensitive to lead concentrations up to 10 ppb is being developed. This constitutes the biosensor that fluoresces in proportion to the presence of lead. b) Bacteria response is imaged using a microprocessor (ESP32) with a camera module. This constitutes the optical metrology component of the PlomBOX. c) Data acquisition and control of the PlomBOX is achieved through a Bluetooth connection with the PlomApp, a custom-developed mobile phone application. Data are sent from the PlomApp to a database where a bespoke automated analysis software provides a result of the lead concentration in a sample of water. This paper reports on the instrumentation challenges of developing the electronics for the PlomBOX and on the first prototype.
This article reports the characterization of two High Purity Germanium detectors performed by extracting and comparing their efficiencies using experimental data and Monte Carlo simulations. The ...efficiencies were calculated for pointlike \(\gamma\)-ray sources as well as for extended calibration sources. Characteristics of the detectors such as energy linearity, energy resolution, and full energy peak efficiencies are reported from measurements performed on surface laboratories. The detectors will be deployed in a \(\gamma\)-ray assay facility that will be located in the first underground laboratory in Mexico, Laboratorio Subterráneo de Mineral del Chico (LABChico), in the Comarca Minera UNESCO Global Geopark
We present studies of proton fluxes in the T10 beamline at CERN. A prototype high pressure gas time projection chamber (TPC) was exposed to the beam of protons and other particles, using the 0.8 ...GeV/c momentum setting in T10, in order to make cross section measurements of low energy protons in argon. To explore the energy region comparable to hadrons produced by GeV-scale neutrino interactions at oscillation experiments, i.e., near 0.1 GeV of kinetic energy, methods of moderating the T10 beam were employed: the dual technique of moderating the beam with acrylic blocks and measuring scattered protons off the beam axis was used to decrease the kinetic energy of incident protons, as well as change the proton/minimum ionising particle (MIP) composition of the incident flux. Measurements of the beam properties were made using time of flight systems upstream and downstream of the TPC. The kinetic energy of protons reaching the TPC was successfully changed from \(\sim0.3\) GeV without moderator blocks to less than 0.1 GeV with four moderator blocks (40 cm path length). The flux of both protons and MIPs off the beam axis was increased. The ratio of protons to MIPs vary as a function of the off-axis angle allowing for possible optimisation of the detector to select the type of required particles. Simulation informed by the time of flight measurements show that with four moderator blocks placed in the beamline, (\(5.6 \pm 0.1\)) protons with energies below 0.1 GeV per spill traversed the active TPC region. Measurements of the beam composition and energy are presented.
The upgrade of the ALICE TPC will allow the experiment to cope with the high interaction rates foreseen for the forthcoming Run 3 and Run 4 at the CERN LHC. In this article, we describe the design of ...new readout chambers and front-end electronics, which are driven by the goals of the experiment. Gas Electron Multiplier (GEM) detectors arranged in stacks containing four GEMs each, and continuous readout electronics based on the SAMPA chip, an ALICE development, are replacing the previous elements. The construction of these new elements, together with their associated quality control procedures, is explained in detail. Finally, the readout chamber and front-end electronics cards replacement, together with the commissioning of the detector prior to installation in the experimental cavern, are presented. After a nine-year period of R&D, construction, and assembly, the upgrade of the TPC was completed in 2020.
Secondary discharges, which consist of the breakdown of a gap near a GEM foil upon a primary discharge across that GEM, are studied in this work. Their main characteristics are the occurrence a few ...\(10\,\mu \textrm{s}\) after the primary, the relatively sharp onset at moderate electric fields across the gap, the absence of increased fields in the system, and their occurrence under both field directions. They can be mitigated using series resistors in the high-voltage connection to the GEM electrode facing towards an anode. The electric field at which the onset of secondary discharges occurs indeed increases with increasing resistance. Discharge propagation form GEM to GEM in a multi-GEM system affects the occurrence probability of secondary discharges in the gaps between neighbouring GEMs. Furthermore, evidence of charges flowing through the gap after the primary discharge are reported. Such currents may or may not lead to a secondary discharge. A characteristic charge, of the order of \(10^{10}\,\textrm{electrons}\), has been measured as the threshold for a primary discharge to be followed by a secondary discharge, and this number slightly depends on the gas composition. A mechanism involving the heating of the cathode surface as trigger for secondary discharges is proposed.
